A high-level defection from former vice president Riek Machar's rebel group could impact the latest round of peace negotiations for South Sudan, said a government spokesman on Friday.

"There is a split in the rebel ranks and this split may have an effect on the peace talks,” Information Minister Michael Makuei told a news conference in Juba before leaving for Addis Ababa, where new talks are set to resume.

"Upon our arrival, we need to know with whom we are going to negotiate. There are already two factions and these two factions are already there and as such we will not just go and start talking. We will go and talk with the rebels when they put their house in order,” Makuei said.

'Lone ranger'

Lul Ruai Koang, who was the military spokesman for Machar's rebel group, announced this week that he was breaking away from the armed opposition group. Ruai was also one of its lead negotiators at the long-running peace talks.

He said he had become disillusioned with the way peace negotiations were being conducted, and with Machar himself. Ruai accused the former vice president of being interested mainly in returning to power, not in alleviating the suffering of the South Sudanese people.

The deputy chair of the rebel group's external relations committee, Ezekiel Lol Gatkuoth, downplayed Ruai's defection from Machar's Sudan People's Liberation Movement in Opposition (SPLM-IO). He said Ruai returned to Juba on Thursday accompanied only by his wife, and not with dozens of supporters.

"He did not have a single human being with him, not even a bodyguard," Gatkuoth said. "He is just a lone ranger."

Opposition denial

Gatkuoth firmly denied that Ruai's departure meant the SPLM-IO was disintegrating. He said the SPLM-IO delegation was in Addis Ababa in time for the talks to resume, and is ready to get back down to the business of negotiating peace.

"There is no split at all," he said. "We are waiting for the government delegation. Our chairman is here, our delegation is here, but the government delegation is not yet in Addis."

President Salva Kiir and Machar last met in January on the sidelines of an African Union summit meeting. At those talks, the two men signed a power-sharing proposal put forward by the Intergovernmental Authority on Development (IGAD), the regional bloc that has been overseeing the South Sudan peace process for nearly 14 months. They also vowed to respect a year-old -- and often broken -- cessation of hostilities agreement.

IGAD has given the two sides until March 5 to reach a final peace deal, and until July 9 to establish a transitional government of national unity.

Makuei said that, even as the two sides prepared to reconvene in Addis, rebel forces were attacking government positions in Upper Nile state.

“Even this morning, they have attacked our positions in Nasir," Makuei said. "But nevertheless, all these violations will never change the position of the government in its search for peace."